An External Wastegate (EWG) allows exhaust gases to be diverted prior to entering the turbo. This facilitates lower backpressure at the turbine, allowing for increased boost control, faster spool-up and greater top-end power. The GrimmSpeed EWG Up Pipe has a larger internal diameter than your stock unit, allowing a higher volume of exhaust gas to reach your turbo more efficiently. This helps maintain boost levels further into your RPM range. Depending on your specific setup, these improvements can net a 10-40 HP increase. An internal wastegate can create a larger amount of turbulence in exhaust flow through your turbine housing; moving to an external wastegate eliminates much of that turbulence and isolates the turbo from what little turbulence still exists as your wastegate opens and closes.